TROJI THE USUAL STRUCTURE OF SEEDS. 363 



There are some cases in which this early opening of the 

 ovarinm, instead of being, as in the preceding instances, 

 an irregular bursting, apparently caused by the pressure of 

 the enlarged ovula, is a regular dehiscence in the direction 

 of the suture. Of this Sterculia platanifolia and S. colo- 

 rata are remarkable examples ; their folliculi after opening, 

 which takes place long before the maturity of the seeds, 

 acquiring the form and texture of leaves, to whose thickened 

 margins the ovula continue firmly attached until they ripen. 

 Another example of this early and regular dehiscence occurs 

 in an undescribed genus of the same family, which differs 

 from Sterculia platanifolia in its pericarpium having a 

 terminal wing and a single seed. 



In the specimens of a plant lately sent from Brazil by 048 

 Mr. Sellow, I observe a similar economy. In this case the 

 ovarium, which is originally unilocular with five parietal 

 placentiB, soon after fecundation opens regularly into five 

 equal foliaceous valves, to the inner surface of each of which 

 an indefinite munber of ovula are attached. 



The genus Reseda, whose capsule opens at top at a very 

 early period, may be considered as affording another in- 

 stance, though much less remarkable, of the same anomaly. 

 And it is possible that this may be the real structure in 

 certain cases of which a very different view has been 

 taken. 



In tlie instances of naked seeds now given, the bursting 

 of the pericarpium precedes the distinct formation of the 

 embryo, while the proper coats of the seed remain entire 

 till after its separation from the parent plant, and germi- 

 nation has commenced. 



It may not be uninteresting to contrast this economy 

 with that of the Mangroves and other plants of tropical 

 countries, which grow on the shores, and within the 

 influence of the tide. In many of these the embryo, 

 long before the seed loses its original attachment, acquires 

 a very considerable size ; and the first effect of this un- 

 usual development is the rupture, in most cases succeeded 

 by the complete absorption or disappearance, of the proper 

 integument of the seed. In some instances the develop- 



